Vernacular to Contemporary | PDEC | An ‘Adaptation’ – Part II

Last week in Part I, we introduced a Vernacular to Contemporary Adaptation – PDEC – Passive Downdraft Evaporative Cooling. A Vernacular ventilation strategy – Wind Catchers, which is being adapted to Contemporary buildings. We also looked at diagrams explaining the 3 main principles in this Adaptation.


This week we look at Pros and Cons of this technology for Contemporary use.


1) Energy Saving

a) Decrease cooling demand

Temperature Drops of upto 13oC can be achieved1. When the outdoors sizzle at close to 44oC, the indoors are at around 30oC.

Night Ventilation using PDEC towers decreases cooling demand and operating time of the primary cooling system the following day3.

b) Less Fluctuations

Indoor Temperature fluctuations of around 3-4oC can be seen over 24 hours, when the outside Temperature fluctuations are between 14-17oC1.


2) Cost/ Applicability

a) Short Payback Period

Electrical Consumption savings helped achieve payback of additional capital cost in less than 1 year for the Torrent Research Centre, Ahmedabad.1

b) Can be used in new / existing buildings with simple construction elements at relatively low cost.


3) Location

a) Applicable in areas without wind

As Air movement is created by momentum transfer from water to air and density difference; the technology can be applicable in areas without wind 4, 5.


4) Cleaner Air

a) Evaporative Cooling

The air is cleaned during the evaporative cooling process 6.


Cons –

1) Capacity

The cooling capacity maybe insufficient in certain cases, and could need conventional cooling as well 4.


2) Cost/ Applicability

a) High Water Consumption 6.

b) Short life of Water Pads


3) Climate Dependency

a) Works best in Hot & Dry Conditions

The technology maybe most effective in hot and dry conditions. However, buildings can be designed to adapt to other conditions and seasons. For example, in the Torrent Research Centre, the system operates normally in the dry season. In the monsoons, the water spray is not used, whereas in Winters, the openings to the rooms and shafts can be controlled (opened or closed) by the occupants 1, 4, 6.


sum up


How do You feel about this Vernacular ‘Adaptation’ for Contemporary Buildings?

Have you come across other such Adaptations?

What are your thoughts on the Practicality of this Technology? Let us know!


Video Source: 

The rchitecture Gazette

Music Source:

“Virtutes Instrumenti” Kevin MacLeod (
Licensed under Creative Commons: By Attribution 3.0 License


  1. A&D, ADEME, INDé (Mohan S.), Palacios D. | Case Study II: The Torrent Research Centre in Ahmedabad, by Abhikram. Architecture & Developpement.
  2. Zaveri P, Patel N. Abhikram | Projects | Torrent Research Centre, Ahmedabad.
  3. Paanchal JB, Mehta N. “A Review on Design of Passive Down Draft Evaporative Cooling in Commercial building.” 2017;3(2).
  4. Bowman, N. T., Eppel, H., Lomas, K. J., Robinson, D., and Cook, M. J. “Passive Downdraught Evaporative Cooling I. Concept and Precedents.” Indoor + built environment 9.5 (2000):284-290.
  5. Etzion, Y., Pearlmutter, D., Erell, E., and Meir, I. A. “Adaptive architecture: Integrating low-energy technologies for climate control in the desert.” Automation in construction 6.5 (1997):417-425.Ford, B. “Passive downdraught evaporative cooling: principles and practice.” Environmental Design. Architectural Research Quarterly 5, Cambridge University Press (2001) : 271-280.
  6. Givoni, B. “Performance of the Shower Cooling Tower in Different Climates.” Renewable Energy, 10, 2/3 (1997):173-178.
Vernacular to Contemporary | PDEC | An ‘Adaptation’ – Part I

Wind Catchers, traditionally known as Badgirs or Malqafs are Natural Ventilation devices. They have successfully been used in countries like Iran, Egypt, Pakistan, Afghanistan for many years.

This Vernacular Method is being ‘Adapted’ and utilized in various Contemporary Buildings. One such adaptation is the Strategy known as PDEC or ‘Passive Downdraft Evaporative Cooling’.

We use diagrams of the Torrent Research Centre, Ahmedabad; to discuss this technique.

3 main Principles are at play-

  1. Evaporative Cooling – Water Sprays Cool the Warm Air Entering the tower
  2. Cool Air Sinks – This Moisture Induced Air is Heavier and thus Sinks
  3. Warm Air Rises – Warm Air in the rooms is Lighter and Rises

This sets up a Loop of Air.

The Project achieves a temperature drop of upto 13oC. When the outdoors sizzle at close to 44oC, the indoors are at around 30oC1. The Building incurred Additional Civil Costs of 13% for its Strategies. However, Energy savings helped payback the investment in less than 1 year2!


How do You feel about this Vernacular ‘Adaptation’ for Contemporary Buildings? Have you come across other such Projects?

What are your thoughts on the Practicality of this Technology? Let us know!

Look out next week, for the Pros | Cons of this Strategy in – Vernacular to Contemporary | PDEC | An ‘Adaptation’ – Part II


Video Source: 

The rchitecture Gazette

Music Source:

“Virtutes Instrumenti” Kevin MacLeod (
Licensed under Creative Commons: By Attribution 3.0 License


  1. A&D, ADEME, INDé (Mohan S.), Palacios D. | Case Study II: The Torrent Research Centre in Ahmedabad, by Abhikram. Architecture & Developpement.
  2. Zaveri P, Patel N. Abhikram | Projects | Torrent Research Centre, Ahmedabad.
Drip Irrigation Case Study – Follow up

Following our case study Article and Video – Drip Irrigation in the City, we received expert response from a Ranchi, India based Civil Engineer, with almost 40 years’ experience.

Based on this discussion, and feedback, this week’s article outlines possible issues that may arise with use of this technology in Residential colonies.

In Case study 1 (original Case Study -Residence A), the Balcony A in question lies adjacent to a plumbing Shaft A, containing supply water pipes to the house. Thus, the plumber can easily provide a water connection (Source for the Drip Irrigation System) from this shaft to the balcony.

However, in Case Study 2 (Alternative
Scenario – Residence B),
the positioning of shafts is different. The Shaft B in the house (Residence B) is placed far from the Balcony. This makes it difficult to provide a water source for the Drip

The Shaft C, which offers a more direct route to Balcony B, contains water supply pipes belonging to another flat (Residence C). Thus, the plumber would be unable to draw a connection from this shaft.


Such technology could be Integrated at earlier Design stages in future Residential constructions. Thus, shaft and water supply lines could be planned accordingly, for convenience to Residents and to save Water.

We look forward to more such expert opinions, feedback,
comments. These help us move towards further Sustainable Solutions, for our evolving Built and Urban Environments.

TAG Videos | Drip Irrigation in the City

Video Source | The ꓥrchitecture Gazette

Music Source | “My Best Melody” catatau5 | Link

References / Additional Reading |

1) Alliance for Water Efficiency |

2) CINAGRO™ Products |

‘Drip Irrigation in the City’ | A Case Study

This week we document Drip Irrigation used for balcony garden irrigation. The Case study is a 1000 sqft. flat dwelling, housing 2 aging persons. Having a large ground garden, while living in a metro city is a luxury most cannot afford. So, many people nurture beautiful balcony gardens. Often aging parents or grandparents may be living alone and looking after these spaces. They may or may not have access to domestic help for daily watering of plants. New developments are often also plagued with water shortages. Tiled balconies can become messy and slippery with pipe or bucket watering, thus posing a danger to aged people living alone.

We thus explore this technology, used in our case study, that may be able to address the above issues. It could remove unnecessary risk and make life a little more convenient for aged people.

The Nuts and Bolts

Looking at 3 main details

1) Origin – Tap, Tap Connector, Elbow Connector, Main Pipe

2) Route – Main Pipe, Elbow/ Tee/ Straight Connectors

3) Destination – Main Pipe, Feeder Pipe, Stake/Anchor to hold Feeder Pipes in the soil of pots, Drip Emitter

Some advanced kits also include automatic timers for scheduling the watering cycle.


The whole kit could cost between ₹ 300 to above ₹ 7000 (around $4 – $100 depending on company, number of plants)

Pros and Cons

The Pros and Cons are based on feedback for the technology by the owners. 

Note: The products utilized by the owners in the Case Study are by a company called CINAGRO™.  We are spreading information about the ‘adaptive’ use of this technology to solve important city issues. We however, are NOT endorsing the products/ company in question. You could search for Drip Irrigation Garden online. There are various companies that sell/ install such products.

Hope these details help you make decisions for your homes and the homes of other aging people with similar requirements.

Have you used a similar technology in your projects? Tell us about your experience. Did you face any other issues than the ones described above?

Do you think this ‘Adaptation’ can help address Emerging city needs?

Let us know!

Video Source: 

The rchitecture Gazette

Music Source:

“My Best Melody” catatau5 | Link


  1. Alliance for Water Efficiency
  2. CINAGRO™ Products

Cool Roofs

While researching various Passive Strategies and Technologies for the Building Envelope, we came across ‘Cool Roofs‘. We realized that this is a simple, low cost technology with large potential benefits. These include – Energy savings, Reduction of Urban Heat Island Effect and Greenhouse Gas Emissions, enhanced Durability of roofs, and Resilience to extreme heat 1.

Thus, this week’s Article and Video are dedicated to this important idea. The Video 2 , 3 , 4 outlines the Need for Cool Roofs and how they Protect Buildings. In the Article, we cover Initiatives by various parties working in the direction. We also look at some successful Case-Studies that could become models for future developments.

Due to multiple possible benefits, the technology has caught the attention of International actors, Indian central, state and local governments, as well as the Private sector. Their attempt is to use Cool Roofs for large scale Impact at the Building and Urban scales.


  • The Bureau of Energy Efficiency [(BEE), Government of India, Ministry of Power], has prepared a ‘Cool Roof Design Manual‘ 2 to spread technical information about Cool Roofs for the Composite Climate Zone of India.
  • A Fact Sheet 5 and Issue brief 6 have been released by Natural Resources
    Defense Council (NRDC) and Partners to showcase local projects, and to spread the message, so that action can be scaled up.
  • Green Building Rating systems like LEED, GRIHA, IGBC need compliance with the Energy Conservation Building Code (ECBC) norms. ECBC specifies minimum cool roof values (reflectance and emittance), for roofs with different slopes 6.
  • IIIT Hyderabad Cool Roof Calculator – The simulation tool by IIIT Hyderabad, uses a base and design case for testing various roof conditions in certain cities of India. A percentage change in cooling energy can be compared 2 7.

The above efforts are helping common people as well as experts to understand and utilize Cool Roofs, by providing technical information, tools and answers to common questions. The following examples showcase successes in the field.


  • Ahmedabad’s Cool Roof Initiative, as part of its ‘Heat Action Plan‘ aims to convert 3000 roofs in 6 zones to Cool Roofs. This is being undertaken by city staff and student volunteers. They are using white lime paint, which costs as little as ₹0.50 per square foot 5.
  • Hyderabad is also witnessing a Cool Roof Initiative as part of its Building Energy Efficiency Program. The Pilot included 25 city roofs in low income areas. A High-Density Polyethylene (HDPE) cool roof membrane (costing ₹13 per square foot in Hyderabad) was supplied by Dupont as part of their CSR initiative 1.
  • The Indore and SuratCool Roof Project‘ is using local success stories to make a case for cool roof policies in the future. The project consists of over 100 households.  They are using simple materials such as lime concrete, broken earthen pots, China mosaic tiles  6.
  • A Joint study was conducted by International Institute of Information Technology, Hyderabad (IIIT) and Lawrence Berkeley National Laboratory (LBNL) on 2 office buildings in Hyderabad. The studies saw a drop of approximately 20°C in Roof surface temperatures after application of cool roof coating 2.

We leave you with the following questions –

  • Have you used ‘Cool Roofs’ in your Project? Do you know of any projects using ‘Cool Roofs’?
  • What Benefits have you felt after application of the ‘Cool Roof’ technology?
  • What Problems did you face?
  • What kind of Assistance if any, did you receive from the Government or any other organisations?

Let us know! We would love to provide a platform, to showcase your project and spread more useful information.

Video Source: 

The Architecture Gazette

Music Source:

“My Best Melody” catatau5 | Link

Data Sources:

  1. Jaiswal A, Bhagavatula L, Awasthi A, Sarkar S. Keeping It Cool: Models for City Cool Roof Programs. National Resources Defense Council. Published 2018. Accessed November 27, 2018.
  2. Bureau of Energy Efficiency. Cool Roofs for Cool Delhi: Design Manual. Accessed November 27, 2018.
  3. Majumdar M. Cooling homes…heated pockets. The Economic Times Blogs. Published 2013. Accessed November 27, 2018.
  4. Panchkula gets energy-efficient, green government building. Indian Express. Published 2012. Accessed November 27, 2018.
  5. International Institute of Information Technology Hyderabad, Administrative Staff College of India, Indian Institute of Public Health Gandhinagar, Mahila Housing SEWA Trust. Keeping It Cool: How Cool Roofs Programs Protect People, Save Energy and Fight Climate Change.; 2018. Accessed November 27, 2018.
  6. International Institute of Information Technology Hyderabad, Administrative Staff College of India, Indian Institute of Public Health Gandhinagar, Mahila Housing SEWA Trust. Issue Brief – Cool Roofs: Protecting Local Communities and Saving Energy.; 2018. Accessed November 27, 2018.
  7. Cool Roof Calculator v3. CBS, IIT – Hyderabad. Accessed November 27, 2018.
Passive Strategies: Natural Ventilation (b)

Last week we started our series on Passive Strategies in Buildings. We kicked off with Natural Ventilation (a)Why it’s needed, What needs to be doneHow and Factors important for it.

This week we look at Strategies and related Issues for Natural Ventilation.

  1. Zoning
  2. Orientation and Form
  3. Building Depth
  4. Fenestration
  5. Advanced Strategies

(1) Zoning

Building functions can be zoned according to the ventilation strategy for effective management and energy conservation. This is seen in Akshay Urja Bhavan1 where spaces are divided into zones according to setpoints – Apex, Controlled and Passive. Only around 12% of the area is air-conditioned. Mist cooling systems are used for the Controlled and Passive zones.

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(2) Orientation and Form

Buildings should preferably be oriented between 0o and 30o with respect to the prevailing wind direction2. The building form can incorporate courtyards or verandahs (transitions zones between inside and outside) for increased ventilation and thermal comfort. These features temper down the harshness of the exterior environment, providing shade and cool breezes in summer.

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(3) Building Depth

unit thick principle
Unit Thick Principle in 2 projects by WOHA

A building depth of around 15 meters or less would enable Natural Ventilation and Daylighting. This is an assumption based on our research of many buildings by WOHA applying their Unit thick Principle. Some buildings may not be able to achieve less depth due to larger functions such as Industrial labs.

Solution | Fragmentation of Form – Such buildings could employ courtyards or atriums to break the overall form, thus enabling light to penetrate or air to flow better. (eg. Cleantech One) Fragmentation of form is also seen in Indira Paryavaran Bhavan3, where two North-South oriented blocks are separated by a centrally running  public spine.

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(4) Fenestration

  • Location, Sizing, Area – The location and size of windows, should take into account the wind direction and the ‘Living Zone’. The total area of openings should be a minimum of 30% of floor area2.
  • Window to Wall Ratio – The Window to wall ratio (WWR) should fall between 20-40% for Commercial buildings. In any case, it should not exceed 60%4.
  • Operable windows – The windows should preferably be operable with a staggered alignment. Operable windows may present certain issues. In the case of hotels for example, people might leave windows open when the air-conditioning is on, which would affect energy costs. Operable windows could also have safety implications.

Solution 1 | Sensors – Some hotels install sensors that automatically shut off air-conditioning when windows are opened.

Solution 2 | Individual Project Detailing – Safety concerns would need to be addressed in projects individually, through railing design details, selective openings or special locking mechanisms.

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(5) Advanced Strategies

(i) Air Earth tunnels


A 16 km (once campus completed) tunnel network of Air Earth tunnels, will be running 4 m below the ground in NIIT University, Neemrana Campus. Surface temperature and seasonal variations do not penetrate below this depth, keeping air temperature constant throughout the year. Fans will pull cool air through these tunnels. This would then be taken through precipitators to eliminate dust and would be supplied to the building through ducts. The result! – Pleasant 25oC temperatures indoors, without the use of air-conditioning, when temperatures outside are nearing 50oC5.

(ii) Wind Tower

These are utilized widely in desert climates (eg. Iran, Saudi Arabia). Tall towers are built with openings facing the prevailing wind direction. The openings are narrow and the towers may contain misters or other moisture creating devices. As the tall tower catches winds, air moves down the tower, cooling on the way and is used in the building. A similar system using Shower Towers is used at DPR Office, Phoenix.

(iii) Stack effect

According to the principle, warm air from an area would rise, making space for cooler air. This would generate a loop of air circulation. This effect can be seen at building scale or even at room level. In Indira Paryavaran Bhavan, the central courtyard spine coupled with well placed building punctures, generates the ‘Stack Effect’ at the building scale. The IRRAD Building, although using air-conditioning, is utilizing a similar principle. The vents are placed near the floor, instead of the ceiling. Cool air enters the room at a lower level and it rises as it become warm6.

(iv) Displacement Ventilation

In Neemrana University, the cool air from ducts is introduced at lower levels in rooms. This pushes warm air in the room upwards, which is then exhausted through openings in higher parts of the spaces. It is similar to the stack effect, but here an additional push is being provided by the introduced cool air, to get the circulation loop going.

(v) Wind Scoops

Wind Scoops like the one used in CapitaGreen can channel air into a ‘Cool Void’. This brings cool air from a higher altitude, deeper into a high-rise building. Air flow, such as that channeled by CapitaGreen maybe blocked by surrounding buildings in a different scenario.

Solution | City Planning and Studies – This leads to the need for city planning and studies like Computational Fluid Dynamics (CFD) to ensure these strategies are workable at a city level. This would help avoid “dead air zones”, wind canyons and other undesirable wind related events. This becomes especially important in city centers with greater density and multiple high-rise structures.

(vi) Solar Chimney

The DPR Phoenix Regional Headquarters in Pheonix, Arizona use solar chimneys to exhaust warm air from the building.

(vii) Evaporative cooling

This technique utilizes the latent energy used to convert liquid to gas. As water evaporates, its phase changes, which results in a cooling effect. This technique has been used widely in desert coolers.

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That’s all for this week. Hope this was useful! As always, please let us know your thoughts, suggestions, queries, opinions. Your views will make this exploration richer!

Thank you!



  1. BEE, USAID, PACE-D. Case Studies – Akshay Urja Bhawan. NZEB.
  2. BEE, USAID, PACE-D. Knowledge Centre – Natural Ventilation. NZEB. Accessed September 9, 2018.
  3. CA(NDR), CPWD. Sustainable Architectural Built Environment.
  4. GRIHA, TERI. GRIHA V-2015.; 2015. Accessed September 9, 2018.
  5. Bhandari P. Let buildings breathe. Times of India Jaipur. Published 2009.
  6. Somvanshi A. Simply creative. DownToEarth. Published 2015.
Passive Strategies: Natural Ventilation (a)

Last week we were in conversation with Sustainability Professional Steven Lee from Malaysia. He is currently Principal at Edisi Hijau Sdn Bhd, Kuala Lumpur, Ipoh. Steven has been working with the IT industry for over 20 years, before making the move to Green Technology in 2007. (You could connect with him here – LinkedIn, Twitter)

Our discussion started with the post on Passive Strategies used in CapitaGreen, Singapore and the viability of such strategies in other projects and countries.

Today, we sum up points from this discussion and others that we think could be useful to our readers. We will focus on 3 Essential Passive Strategies – Natural Ventilation, Integration with Greens & Water and Daylighting. This part starts with Natural Ventilation.

Natural Ventilation


Natural Ventilation

Why it is needed ?


Buildings account for 33% of the total electricity consumption in India. (Domestic 24%, Commercial 9%)1. Of this,  HVAC is one of the highest loads accounting for almost 50-60%2.

What needs to be done and effects ?

reduce need

Our effort should be to reduce the need for Air-conditioning, to help reduce energy loads. Less AC use or using air-conditioning at higher setpoints, could result in saving energy. In Residential scenarios for example, after 22oC, every 1oC higher set point equals 3-5% less energy use3.

How ?

Through design, planning, passive strategies like Natural Ventilation, integration with greens and water, we can increase thermal comfort. Thus people will want to use less air-conditioning and this will result in energy use reduction.

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Factors important for Natural Ventilation

(i) Climate

Climate is one of the chief factors determining the feasibility of Natural Ventilation. For example, Natural Ventilation is quite effective in Moderate climates and it may provide considerable relief in Hot and Humid conditions4. However, it could bring discomfort and dust in Hot and Dry Climates. Cold Climates also need protection from chilling exterior winds and might need enclosed conditions.

(ii) Wind direction

The wind direction determines design and viability of Natural Ventilation. Wind rose diagrams are used to understand prevailing directions, frequency, speed and other factors related to wind conditions in any particular area.

(iii) Thermal Comfort and Perception

Thermal Comfort is a complex, often subjective issue determined by multiple factors. Before the advent of AC, buildings were designed according to climate and context. People enjoyed the benefits of fresh air. Now, many occupants prefer fully air conditioned spaces since they have become used to such an environment. There might be instances when the AC is too cold for comfort, but this has become the norm. Enclosed buildings behave like greenhouses2, which then need air-conditioning to cool them down. So, the need is not only to improve thermal comfort , but also address people’s perception related to it.  To address this complex issue, we could look at the following solutions.

Solution 1Custom Thermal Comfort Models – Countries could develop customized thermal comfort guidelines for Design. An example is the ‘Indian Adaptive Comfort Model’ developed by CEPT university. This is part of the GRIHA manual5 and is adapted to Indian local conditions. For example, it provides Indoor Operative temperature values for all cities in India. These are setpoints which are required as per standards to achieve thermal comfort. They are to be monitored during the operation of the building. These models could help optimize setpoints and engage in better AC design.

Solution 2 Hybrid systems – DPR Office in Phoenix, Arizona uses a hybrid cooling system. They have special High Velocity Low Speed (HVLS) fans and operable windows. Cooling is provided by moist air through Shower Towers on the facade. There is also a Solar Chimney exhausting warm air. Only when the conditions are too extreme, they switch on the air-conditioning6. A hybrid cooling system is also being designed for the new School of Design and Environment building NZEB in the National University of Singapore7. The NZEB at CEPT University is planning to utilize optimized natural ventilation coupled with a radiant cooling system2.

Solution 3Common areas could be Naturally Ventilated, (fully or partially) for starters. Since occupants spend lesser time in spaces like corridors, washrooms, lobbies, parking – such efforts might help the acclimatization process. An example can be seen in ParkRoyal Hotel @ Pickering.

park royal

(iv) Pollution and Location 

Natural Ventilation may not be possible if the outside air is polluted. Pollution could be due to traffic, dust from a construction site or other harmful substances, such as emissions from a factory.

Solution 1 | Location – Sensitive functions like schools or hospitals would ideally be located away from such areas.

Solution 2 | Natural Filters/ Barriers – If this is not possible, window opening design could be clubbed with strategies like Vegetation or Earth mounds, to act as noise barriers or to filter pollution.

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That’s all for today. We hope you enjoyed reading the article!

Next week we look at Passive Strategies: Natural Ventilation (b) in which we cover Strategies and related Issues of Natural Ventilation.

For now we leave you with these questions.

Do you know of other Commercial or large projects that are using Passive Strategies?

What do you think of the Passive Strategies mentioned above? Can you spot further practical issues that might arise?

Please share your Sustainability knowledge and experience. Our search for answers continues…..

See you next week.



  1. Rakheja A. Case Study EcoCommercial Building, Noida, India – Adapting To Climate. High Perform Build. 2013:44-52.
  2. USAID India. Net Zero Energy Buildings Initiative.; 2011. Accessed September 9, 2018.
  3. Majumdar M. Sustainable Habitats: Cooling homes…heated pockets. The Economic Times Blogs. Published 2013.
  4. BEE, USAID, PACE-D. Knowledge Centre – Natural Ventilation. NZEB. Accessed September 9, 2018.
  5. GRIHA, TERI. GRIHA V-2015.; 2015. Accessed September 9, 2018.
  6. GreenCE. Aggressively Passive: Confronting the Comfort Status Quo. Accessed September 9, 2018.
  7. NUS S. NUS breaks ground on its first Net-Zero Energy Building today! Published 2016. Accessed September 9, 2018.
E@BS 3/5: Commercial – CapitaGreen


cover capita
CapitaGreen in the Central Business District of Singapore [Image via GreenA Consultants, Singapore]
CapitaGreen is a 82,000 sq.m. GreenMark Platinum building. It is a 43-floor skyscraper in the Central Business District of Singapore designed by Architect – Toyo Ito (2). It is at less than 10-minutes walk, South-East from Park Royal, Pickering – our previous project under study. The Skyscraper has multiple sustainable features as elaborated below; which lead to energy savings of around 4.5 GWh /year (1).

Park Royal and CapitaGreen in Central Business District Singapore; Source: OneMap Singapore


  • Vertical air movement
  1. 45 meter (2) tall wind-catchers atop the skyscraper are oriented towards the prevailing wind direction (1). Designed to scoop winds at this elevation, they channel air down a core known as the ‘Cool Void’ (5).

vertical air movt
Section diagram showing Vertical Air movement, scooping wind from above and bringing it to lower levels; Graphics: Author

  • Horizontal air movement
  1. Air from the ‘Cool Void’ spreads horizontally through the levels, reducing load on the air-conditioning system.

    hori air movt
    Plan diagram showing wind from the ‘Cool Void’ spreads horizontally; Graphics: Author
  2. The facade is created of 2 layers of glass separated by 2 meters. The outer layer is a complex permeable arrangement of flat glass panels and narrower glass fins (7), allowing air to circulate. This layer also shelters the vegetation between the 2 layers of glass.

    Double Skin Facade for air circulation and protecting plants; Image: Green A Consultants
  • Unit thick principle
  1. This building has a large footprint of around 50 m X 60 m. Thus the Unit Thick Principle, which would require a footprint width of 15 m or lower may not be applicable.*

*The Unit Thick Principle, is a design technique applied by WOHA Architects, Singapore; in many of their projects. The figure ’15 m’, is an assumption based on multiple WOHA Project case-studies.


According to Toyo Ito, Singapore has lost a lot of its forests and green (3). This building shows his effort to replace the lost horizontal green, Vertically! The plants will be irrigated using various water-saving techniques such as Rain Water Harvesting (5).

  • Vertical Green spaces –
  1. Almost 55 per cent (2) of the perimeter of the facade is covered with flourishing plants and vertical greenery.
  2. The East and West facades that are usually more difficult to shade, have larger (6) amounts of greenery.

    vertical green
    Axonometric diagram showing Vertical Greenery; Graphics: Credits below
  • Horizontal Green spaces –
  1. Level 5, 14 and 26 have Sky Terraces
  2. There is a Sky Forest on Level 40 (1)

    hori greens
    Sectional diagram showing location of Sky terraces and Sky forest; Graphics: Author


Box 1: Addressing East and West Facades

These faces of the building are difficult to shade, as they receive low angle rays from the rising and setting sun. Common shading features such as horizontal projections, usually fail in such situations. Our case-studies explain methods to address these tricky areas of the building.

  • Park Royal – Using self-shading form projections
  • CapitaGreen – Larger amount of greenery to shade the facades


  1. Sun-Pipes (1) are used at restaurants and gyms. Sun-Pipes are light tubes or tunnels, used for transmitting natural light usually from the roof, to areas less accessible to daylight. Our post on E@BS, talked of DPR’s Phoenix regional office, which also utilizes solar tubes to bring natural light to office spaces.
  2. CapitaGreen has one of the highest floor to ceiling heights for office buildings – 3.2 m. This along with large windows, allows natural light to enter and reduces the need for artificial lighting (6).


This building along with Park Royal, demonstrates how Passive and Sustainable design can be implemented in Commercial buildings, despite budget/ space constraints and strict program controls.


We hope you enjoyed this segment. The post raises further questions that we will try and answer in future posts –

We saw that CapitaGreen has 2 main large sustainable features that extend across the length of the building – the ‘Cool Void‘ Core and the Vertical Green facade. These features have multiple benefits such as –

  • The Cool Void as well as the Greenery provide cooling, thus reducing load on air-conditioning.
  • The Greenery provides cooling of the surroundings through evapotranspiration, and thus positively impacting micro-climate and reduces the Urban Heat Island effect.
  • The plants help provide cleaner air through photosynthesis and also create general feeling of well-being (4) among occupants.

However, CapitaGreen is a large commercial building with multiple tenants. When occupied, it is possible that conflicting questions might arise as follows –


Q) Which party would be in-charge of maintenance of the facade and greenery at various levels? (Centrally managed or by tenants?)

Q) The continuous internal core has an interface with multiple offices and organizations. Again, who would be responsible for maintenance? (Centrally managed or by tenants) Would this interface pose any security or privacy issues?

Q) Are there any Sustainable guidelines for future tenants to follow regarding materials, furniture, lighting, fixtures – to maintain the Green Mark Platinum standard? (This could be similar to LEED BD+C: Core and Shell, where the tenants are given design and construction guidelines, to educate them in implementing sustainable design and construction features in their tenant fit outs)

We leave you with these questions for now. Feel free to let us know answers to the above, or your thoughts, suggestions, queries, opinions. Your views will make this exploration richer.

Thank you and see you next week!

Graphics : All graphics are produced as part of a team project for M.Sc. Integrated Sustainable Design at National University of Singapore (Building Semester – Stage 1 – Complex Living Systems). Group Members – Gajender Kumar Sharma, Aditi Bisen, Huang Hongbo, Zhao Yanming
Text: Aditi Bisen

References/ Additional Reading:

  1. GreenA Consultants. Capitagreen:: GreenA Consultants. Accessed July 8, 2018.
  2. CTBUH. CapitaGreen – The Skyscraper Center. Accessed July 8, 2018.
  3. Zachariah NA. Toyo Ito’s “big tree in the city”, Home & Design News; Top Stories – The Straits Times. Accessed July 8, 2018.
  4. Macdonald F. BBC – Culture – Ten of the world’s most incredible rooftops. Accessed July 8, 2018.
  5. CapitaLand Commercial Trust. CapitaGreen | CapitaLand Commercial Trust. Accessed July 8, 2018.
  6. RSP. CapitaGreen | RSP Architects Planners & Engineers’s Portfolio. Accessed July 8, 2018.
  7. RWDI. CapitaGreen – RWDI Consulting Engineers and Scientists – RWDI. Accessed July 8, 2018.
E@BS Segment 2/7: Commercial – Park Royal Hotel

Park Royal hotel

Park Royal Hotel, Pickering, Singapore; Source: b

Park Royal at Pickering is a 7500 sq.m. Hotel in the thick of Singapore’s Central Business District, facing a now famous Hong Lim Park. The hotel has various sustainable features (elaborated below), that lead to approximately 30 per cent (f) energy savings in operation (using a conventional building of similar scale and functions as base case). Due to these features, it has received the GreenMark Platinum rating certification from Singapore’s Building Construction Authority.



  • Horizontal air movement
  1. Despite being a commercial project, the property shows generosity, by providing a large public interface on the ground floor. This enables Horizontal air flow, thus improving thermal comfort for the area.
  2. The corridors, lobbies and common wash rooms are all naturally ventilated with fresh air (c).
  3. The entrance to the above-ground car park is concealed with plants and is also naturally ventilated.

hori air movement
Plan and section diagrams showing horizontal air movement through Public space; Graphics: Credits below

This natural ventilation in humid Singapore conditions, provides relief to occupants. The breeze, coupled with shading measures, can improve thermal comfort conditions; thus reducing the need for artificial mechanical cooling.

Public interface on Ground Floor enabling Horizontal air movement; Source: a

  • Unit thick principle
  1. The plan follows the Unit thick principle with an E-shape, and 15 meter wide extensions. This enables sufficient usable daylight to enter the blocks. The configuration also allows for natural ventilation. For this reason, the guest rooms have operable windows, so that guests can open them for fresh air when they like!
  2. The longer sides of the plan face North and South. The smaller projections from the E-plan, thus face the rising and setting sun rays from the East and the West (e). These projections provide self-shading to the block. Thus, guest rooms can have large glazing for views, without the need for additional screening.

unit thickness
Plan diagram showing Unit thick Principle; Graphics: Credits below




Park Royal is famous for integration of Green with its architecture, often referred to as a Hotel and Office in a Garden (d). The project handles this integration with great sensitivity, effectively addressing commonly raised issues of landscape water and maintain costs. The overall cost for landscaping the hotel, worked out to less than 1 per cent of total construction costs (c)!

  • Vertical Green spaces –
  1. Green walls and creepers supplement the shade provided by the self-shading form. These plants also enhance the biophilic experience for guests.
  2. The West facade is a textured wall planted with Ferns – plants that can grow in shade, come in various sizes, require less nutrients,  and need little to no maintenance (d).

vertical green spaces
Section diagram showing Green walls, creepers and water basins – lining the corridors for Natural ventilation and cooling; Graphics: Credits below

Park Royal Corridor with Green and Blue; Source: c

  • Horizontal Green and Blue spaces –
  1. Every 4th level of the 16 storey building, has Sky gardens with landscaping following certain sustainable principles (cd) –
    • Species – Plant selection to find native species that are suitable to the climate.
    • Medium – Choosing the right medium to provide nutrients, and to support roots.
    • Restraint – Proper restraint, to keep the medium from dropping or washing off in rain.
    • Access – for maintenance of the green facade.
  2. The elevated areas of green act as stepping stones for biodiversity movement.
  3. Water bodies include pools on the podium level,  a waterfall and shallow water basins lining corridors. These water features accent the cooling effect created by air movement and shading.

hori green blue
Horizontal Green and Blue spaces; Graphics: Credits below


  • Site integration with Green and Blue 
  1. The project acts as an extension of the green, from the facing Hong Lim Park. It creates around 15,000 sq.m. of green area on the building. This is equal to the entire area of the park, and almost 2 times the gross floor area of the Hotel. The property creates a lush ecosystem attractive to human visitors, birds, insects, small animals.
  2. Park Royal is an example how integration of Green and Blue, can produce positive effects on the environment, such as (c) –
    • Reduction of Urban heat Island effect by shading hard surfaces and evapotranspiration
    • Improving the quality of air by filtering pollutants; absorbing carbon dioxide  and adding oxygen to the air through photosynthesis

Park Royal on Pickering, facing Hong Lim Park – One Map Singapore


The project demonstrates, that despite constraints of space and the need to build higher, Sustainability and Integration with Green and Blue can be achieved. Park Royal not only accomplishes this objective, but does it in grand style, thus becoming a landmark case study for commercial buildings globally.



We hope you enjoyed this segment! We interrupt this Chain of posts on E@BS, to introduce a feature ‘Q & A‘ column next week. This will include further details on the sustainability of Green and Blue, in the Park Royal hotel.

As always, we would love to hear your thoughts, suggestions, queries, opinions.

The Architecture Gazette is now on –


See you next week. Thank you!



Graphics : All graphics are produced as part of a team project for M.Sc. Integrated Sustainable Design at National University of Singapore (Building Semester – Stage 1 – Complex Living Systems). Group Members – Gajender Kumar Sharma, Aditi Bisen, Huang Hongbo, Zhao Yanming
Text: Aditi Bisen



References/ Additional Reading:

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